The use of cloud-based storage services has rapidly expanded in the past few years. Use of storage services such as DROPBOX®, GOOGLE DRIVE®, MICROSOFT ONEDRIVE®, BOX®, APPLE ICLOUD®, etc., and others has become ubiquitous for many users. Cloud-based storage provides a number of benefits, such as universal access (files are accessible from substantially any device with Internet access), automatic replicated back-ups, and sharing, which enables documents to be shared across groups of users. Both GOOGLE® and MICROSOFT® also provide cloud-based editing of documents under which multiple users can concurrently edit the same document.
While the benefits of Cloud-based storage are many, there are also drawbacks. Most significant is there is no way to guarantee that documents stored in the cloud cannot be accessed by hackers. Although hacking instances are rare, hackers develop ever-more sophisticated techniques for breaking into (allegedly) secure data stores and the like, as evidenced by attacks on large companies such as YAHOO®, including a hack in 2013 that assessed 500 million YAHOO® user accounts. Since then, YAHOO® has deployed state-of-the-art security measures, yet hackers have still been able to breach these barriers, including hacks in 2016 and 2017.
File sharing via cloud-based storage services creates an additional problem. For example, DROPBOX® employs a local DROPBOX® application that syncs with storage of documents in DROPBOX® data centers. Access to “local” DROPBOX® folders are seamlessly supported by MICROSOFT WINDOWS® and APPLE® OS X operating systems, enabling users to access the folders in the same manner as other folders. At the same time, when documents are added to a DROPBOX® folder or an existing document is saved, the added document and/or updated version of an existing document is saved to the DROPBOX® cloud. The result of this functionality is that when a document is shared, a copy of the document is not only maintained in a DROPBOX® data center, but each user who the DROPBOX® document or folder containing the document is shared with will have a local copy of the document on his or her machine (or in many cases, on multiple machines). As a result, if any of the user machines is hacked, it is possible that a copy of any shared document might be accessed. Moreover, since most users do not use built-in encryption functionality provided by operating systems such as WINDOWS BITLOCKER® and APPLE's FILEVAULT®, the documents are stored “in the clear,” meaning documents accessed by a hacker can be easily read.
In many instances, documents stored in the cloud and/or shared with others via a cloud-based storage service may include personal and/or confidential data, such as social security numbers, credit card numbers, e-mail addresses, and phone numbers. As used herein, the personal and/or confidential data, as well as other types of sensitive data, private data and personally identifiable data are referred to as “personal threat data” or “threats.” Oftentimes, users are unaware of the existence of such personal threat data within their documents. Additionally, they may be unaware that documents they have shared contain personal threat data. In some cases, users inadvertently share the wrong folders and/or share folders with people they did not intend to share the folders with, exposing personal threat data to these users.